Study unlocks optimal conditions for enzymatic acrylamide reduction

15-Nov-20102010-11-15T00:00:00Z - By Nathan GrayNathan Gray

Intermediate levels of the enzyme asparaginase, and low temperatures, may be the ideal conditions for low acrylamide formation in biscuits, suggests a new study.

According to findings published in Food Chemistry, scientists from the Dublin Institute of Technology in Ireland report that their study showed a strategy “to assess the benefit of asparaginase in reducing the acrylamide formation in biscuits for managing the industrial process.”

“The model used in this study allowed for the assessment of the effect of the natural variability associated to the baking process in final acrylamide concentration, besides the variation of the selected dependent variables,” said the researchers, led by DrJesus Frias.

Acrylamide

In 2002 Swedish researchers found the carcinogenic compound acrylamide was present at high levels in many foods . The discovery grabbed international headlines, alarming consumers and food safety authorities globally.

Since then acrylamide has been the focus of much research, and had been found in many foods, including, bread, crackers, biscuits, deep-fried products and coffee.

Epidemiological studies have since reported that everyday exposure to acrylamide from food substances is too low to be of carcinogenic concern - however in March 2010 the European Chemical Agency added the compound to its list of ‘substances of very high concern’ .

There are various approaches to reduce or prevent the formation of the compound, and asparaginases are one of the more established forms. Indeed, at the tail-end of 2007 the Confederation of the Food and Drink Industries of the EU (CIAA) included asparaginase in the new version of its Acrylamide Toolbox, a move seen to validation the efforts of companies that have developed commercial solutions using the acrylamide-reducing enzyme.

Both DSM's Preventase and Novozymes' Acrylaway are asparaginases, but they stem from different production strains: Novozymes' from Aspergillus oryzae and DSM's from Aspergillus niger.

The two enzymes are understood to share the same aim - that is, to convert free asparagine into aspartic acid, another animo acid that does not form acrylamide. The nutritional properties are unaffected, and so are the browning and taste aspects.

Despite “a number of patent applications concerning different processed foods, such as snack foods, chips, dough foods, etc”, the authors claim that no fundamental modelling of the effect of asparaginase on this the formation of acrylamide is available.

“Due to the complexity of the relationship between the environmental variables involved in the enzymatic process and acrylamide formation, the effective enzymatic activity and the final acrylamide concentration achieved, a study of these relationships are needed to find the best conditions to minimise acrylamide formation,” they stated.

Study details

Dr Frias and colleagues stated that the variable with the biggest effect on acrylamide formation was the concentration of asparaginase introduced, followed by the effect of temperature. The incubation time of the asparaginase infused dough was reported to be the least important variable.

“This points to the result that, within the present conditions, variations in temperature and/or asparaginase will result in a bigger change in the final acrylamide concentration of the biscuits,” they stated.

The authors reported that within the range of study, an intermediate asparaginase concentration of 500 U per kg, combined with the lowest time and temperature of incubation effectively reduced acrylamide formation in short dough biscuits without affecting the colour of the final product.

Frias and co workers stated that the results contribute to solving the problems associated with optimising formulation to reduce acrylamide formation.

They noted that further studies should aim to not only study the conditions that yield a minimum of acrylamide, but also aim at minimising the variability of acrylamide content in formulations.